The X-Ray Telescope aboard Solar-B: An Overview

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The X-Ray Telescope aboard Solar-B An Overview
Taro Sakao (ISAS/JAXA) and The XRT Team
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XRT Sciences
Imaging observation of the soft X-ray/XUV corona
with advanced imaging/temperature-diagnostic
capabilities
Vast varieties of active, or even non-active,
phenomena in the corona

• Photosphere-Corona connection
• Formation and heating of the coronaincl. energy
  transport, storage, and dissipation
• Outer-corona investigationextending to CME and
  solar wind investigations

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Investigation of Photosphere-Corona Connection
with XRT
Coronal Behavior
Transient Brightenings ?
Immediate Response
Photospheric Magnetic Activity
Time scale minutes Spatial scale 1 arcsec
Trigger ?
?
Large-Scale Coronal Phenomena ? Eruptive
flares CMEs...
Reservoir ? Energy Storage Increase Spatial
Scale
Storage
Release
Time scale days Spatial scale AR
SOT
XRT / EIS
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Coronal Activity Assoc. with Evolution of an
Active Region (from Morita McIntosh 2005)
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Typical Flare Evolution in the Growing Phase
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Typical Flare Evolution in the Large-Flare- Produc
tive Phase
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(Morita and McIntosh 2005)
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• Investigate
• Temperature structure of the corona (both hot
  cool loops)
• Pre-flare evolution leading to energy release
• Long-term evolution of coronal magnetic
  structure
• accompanying flare energy release,
  particularly for entire active regions
• together with photospheric magnetic evolution

(Morita and McIntosh 2005)
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XRT Advanced Features over Yohkoh SXT

• Imaging/temerature-diagnositic capabilities for
  low-temperature (lt 1MK) plasmas Observe entire
  SXR/XUV phenomena in the corona With
  back-thinned CCD together with optimum focal
  plane filters
• Highest-ever achieved angular resolution as GI
  imager, with wide FOV (covering the whole Sun)
  1 arcsec pixel size Cadence as high as, or
  even better than, SXT High-cadence (?1 s)
  observation with small FOV available
• Adjustable Focus PositionAdds variety in
  observations Highest angular-resolution (1
  arcsec) for SOT/EIS FOV Full-sun observation
  with 23 arcsec

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XRT Advanced Features over Yohkoh SXT

• Imaging/temerature-diagnositic capabilities for
  low-temperature (lt 1MK) plasmas Observe entire
  SXR/XUV phenomena in the corona With
  back-thinned CCD together with optimum focal
  plane filters
• Highest-ever achieved angular resolution as GI
  imager, with wide FOV (covering the whole Sun)
  1 arcsec pixel size Cadence as high as, or
  even better than, SXT High-cadence (?1 s)
  observation with small FOV available
• Adjustable Focus PositionAdds variety in
  observations Highest angular-resolution (1
  arcsec) for SOT/EIS FOV Full-sun observation
  with 23 arcsec

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XRT Advanced Features over Yohkoh SXT

• Imaging/temerature-diagnositic capabilities for
  low-temperature (lt 1MK) plasmas Observe entire
  SXR/XUV phenomena in the corona With
  back-thinned CCD together with optimum focal
  plane filters
• Highest-ever achieved angular resolution as GI
  imager, with wide FOV (covering the whole Sun)
  1 arcsec pixel size Cadence as high as, or
  even better than, SXT High-cadence (?1 s)
  observation with small FOV available
• Adjustable Focus PositionAdds variety in
  observations Highest angular-resolution (1
  arcsec) for SOT/EIS FOV Full-sun observation
  with 23 arcsec

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XRT Advanced Features over Yohkoh SXT

• Imaging/temerature-diagnositic capabilities for
  low-temperature (lt 1MK) plasmas Observe entire
  SXR/XUV phenomena in the corona With
  back-thinned CCD together with optimum focal
  plane filters
• Highest-ever achieved angular resolution as GI
  imager, with wide FOV (covering the whole Sun)
  1 arcsec pixel size Cadence as high as, or
  even better than, SXT High-cadence (?1 s)
  observation with small FOV available
• Adjustable Focus PositionAdds variety in
  observations Highest angular-resolution (1
  arcsec) for SOT/EIS FOV Full-sun observation
  with 23 arcsec

Telescope performance to be presented by Ed
Deluca-san et al. in the next talk
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XRT Advanced Features over Yohkoh SXT

• Improved on-board observation control by the
  MDP/XRT system Automatic Exposure Control
  (AEC) Automatic Region Selection (ARS)
  Image-based Flare Detection (FLD new feature)
  Table-based Observation Sequence Controle.g.,
  Exposure tracking and stabilization for AEC
• Implementation of pre-flare data buffer memory
  inside MDP Potentially powerful tool for
  detailed observation of the pre-flare corona
  Investigation of pre-flare energy storage and
  release processes

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Wide-FOV Observation of Outer Corona with
Diagnostic Capability on Temperature Structure
2.3 RSUN
LASCO/C2
2.1 RSUN
Yohkoh SXT
XRT FOV for Limb Observation
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Wide-FOV Observation of Outer Corona with
Diagnostic Capability on Temperature Structure

• Frequent observation opportunity for the outer
  corona
• Temperature structure of the corona up to 2
  Rsun (c.f. Foley et al. 1997 Wheatland et
  al. 1997 with Yohkoh data)
• Tracking transient ejections (CMEs, filaments)
  in the corona

2.3 RSUN
LASCO/C2
2.1 RSUN
Yohkoh SXT
XRT FOV for Limb Observation
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FOV vs Cadence
Full-Sun Coverage
Yohkoh SXT
1000
Full-Sun
XRT
Non-flare
(orbit-ave.)
2 pxl size, or Q75 (3 bit/pxl)
100
Cadence (sec)
(w/ adjacent filter motion)
10
Cover SOT FOV
Flare
(w/o filter motion)
(Hardware limit by Telescope)
1
100
1000
Observing FOV Size (arcsec)
Flare Core
Active Region
Global Corona / Heliospheric
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FOV vs Cadence
Full-Sun Coverage
Yohkoh SXT
1000
Full-Sun
XRT
Non-flare
(orbit-ave.)
2 pxl size, or Q75 (3 bit/pxl)
100
Observation with Pre-Flare Buffer
Cadence (sec)
(w/ adjacent filter motion)
10
Cover SOT FOV
Flare
(w/o filter motion)
x 3
(Hardware limit by Telescope)
1
100
1000
Observing FOV Size (arcsec)
Flare Core
Active Region
Global Corona / Heliospheric
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FOV vs Cadence
Full-Sun Coverage
Outer corona investigation
Yohkoh SXT
1000
High-cadence observation on magnetic
configuraiton and temperature evolution
Full-Sun
XRT
Non-flare
(orbit-ave.)
2 pxl size, or Q75 (3 bit/pxl)
100
Flare core with high spatial/temporal resolution
Cadence (sec)
(w/ adjacent filter motion)
10
Cover SOT FOV
Flare
(w/o filter motion)
(Hardware limit by Telescope)
1
100
1000
Observing FOV Size (arcsec)
Flare Core
Active Region
Global Corona / Heliospheric
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Basic Features of the XRT
X-ray Optics X-ray Optics
Optics Optimized Wolter-I-like grazing incidence optics
Focal length 2708 mm
Mirror micro-roughness 6Å expected (mirror characterization analysis in progress)
Aperture size gt 340 mm
Spatial resolution 68 of encircled energy in 2 arcsec (at 0.523 keV)
Wavelength range 6 200 Å
Effective area gt 1.0 cm2 at 0.523 keV
Visible Light Optics Visible Light Optics
Focal length 2708 mm
Wavelength 4305 Å (G-band)
Focal Plane CCD Camera Focal Plane CCD Camera
CCD device E2V (former Marconi)
20482048 back-illuminated (13.5 mm pixel size)
Field of view 3434 arcmin (capable of covering the whole Sun)
Image readout 500 kpixel/s